Micro-fluid ejection devices such as ink jet printers continue to experience wide acceptance as economical replacements for laser printers. Micro-fluid ejection devices also are finding wide application in other fields such as in the medical, chemical, and mechanical fields. As the capabilities of micro-fluid ejection devices are increased to provide a wider variety of applications and capabilities, the ejection heads, which are the primary components of micro-fluid ejection devices, continue to evolve and become larger, more complex, and more costly to manufacture.
One significant obstacle to be overcome in micro-fluid ejection head manufacturing processes is that currently, ejection head chins are a carefully designed conglomeration of several functional blocks combined into a monolithic piece of silicon. Typical functional blocks may include a beater stack, addressing and firing logic blocks, chip memory, power FETs, and voltage regulators. Since all of the functional blocks are fabricated on the same piece of silicon there are design, process, and material constraints that must be in place for the entire chip so as not to damage or degrade any of the individual functional blocks. Such constraints may result in non-optimal versions of the constituent blocks. Accordingly, instead of having an optimal design for each functional block, the resulting overall design of the election head contains less than optimal components. Accordingly, there is a need for improved structures and methods for making micro-fluid ejection head that enable optimization of individual components without significantly increasing manufacturing costs for making the micro-fluid ejection heads.
With regard to the above, an exemplary embodiment of the disclosure provides a micro-fluid ejection head assembly and methods for fabricating micro-fluid ejection heads using separately fabricated electrical, electro-mechanical, and/or fluidic components. The micro-fluid ejection head has at least one base substrate, at least one fluid ejector actuator substrate attached to the base substrate; and at least a first logic component substrate hermetically sealed to the base substrate. The fluid ejector actuator substrate and the first logic component substrate are in electrical communication with each other.
One exemplary embodiment of the disclosure provides a micro-fluid ejection head assembly having separately fabricated electrical components. The micro-fluid ejection head has at least one base substrate, at least one fluid ejector actuator substrate attached to the base substrate; and at least a first logic component substrate hermetically sealed to the fluid ejector actuator substrate. The fluid ejector actuator substrate and the first logic component substrate are in electrical communication with each other.
Another exemplary embodiment of the disclosure provides a method of fabricating a micro-fluid ejection head having substantially optimized electrical components. The method includes separately fabricating a base substrate having electrical contacts and electrical tracing thereon, separately fabricating a first logic component substrate containing logic components for bonding to one of the ejection actuator substrate and the base substrate. The base substrate, actuator substrate, and first logic component substrate are bonded to one another so that there is electrical flow communication among the components and electrical connections between any two of the components are hermetically sealed therebetween.
An advantage of the embodiments of the disclosure is an ability to separately optimize micro-electronic components so that the capabilities of a micro-fluid ejection head may be increased. Other advantages may include hermetic bonding of electrical connections between components so that incidence of electrical component corrosion is minimized. Still other advantage may include an ability to combine components in multiple ways to obtain different products without significant retooling or design changes. The hermetic bonding techniques described herein also provide an ability to increase input/output connections between components to greater than 500, typically greater than 1000, so that logic component substrates can be separately manufactured from the fluid ejection actuator component substrates of a micro-fluid ejection head.
For the purposes of this disclosure, the term “functional block” is intended to be interchangeable with the term “logic block.” In other words, a functional block may provide a logic function or some other function in the operation of the micro-fluid ejection head. Likewise, the term “logic block” is intended to include any type of functional block whether or not the functional block performs a specific logic function.